This invention is in the general field of surgical instruments and is specifically a catheter having a flexible, proximally-manipulated hinge region. The inventive catheter may include a balloon. The catheter may have a shaft of varying flexibility which contains several lumen. The inner, or delivery, lumen generally may be used with a guide wire to access target sites within the body through the flexible, small diameter vessels of the body. The delivery lumen may be also used for placement of occlusive materials, e.g., in an aneurysm. Inflation of the optional micro-balloon, located near the distal tip of the catheter, is effected using the inflation lumen. The push/pull wire tubing contains a wire, which when manipulated, flexes the catheter""s distal tip.
Endovascular therapy has been used to treat different conditions, such treatments including control of internal bleeding, occlusion of blood supply to tumors, and occlusion of aneurysm. Often the target site of the malady is difficult to reach. Because of their ability to access remote regions of the human body and deliver diagnostic or therapeutic agents, catheters are increasingly becoming components of endovascular therapies. Vascular catheters may be introduced into large arteries, such as those in the groin or in the neck, and then pass through narrowing regions of the arterial system until the catheter""s distal tip reaches the selected delivery site. To be properly utilized, catheters are often stiffer at their proximal end to allow the pushing and manipulation of the catheter as it progresses through the body but sufficiently flexible at the distal end to allow passage of the catheter tip through the body""s blood vessels without causing significant trauma to the vessel or surrounding tissue.
Microcatheters, such as those shown in U.S. Pat. Nos. 4,884,579 and 4,739,768, each to Engleson, allow navigation through the body""s tortuous vasculature to access such remote sites as the liver and the arteries of the brain. Although other methods of causing a catheter to proceed through the human vasculature exist (e.g., flow directed catheters), a guidewire-aided catheter is considered to be both quicker and more accurate than other procedures. Catheters with deflectable or variable stiffness distal ends (which increase the flexibility of the catheter""s distal end) have been disclosed in U.S. Pat. No. 6,083,222, to Klein et al; U.S. Pat. No. 4,983,169, to Furukawa; U.S. Pat. No. 5,499,973, Saab; and U.S. Pat. No. 5,911,715, to Berg et al.
The addition of a fluid-expandable balloon on the distal end of the catheter and a coupler on the proximal end allows various percutaneous medical treatments such as pressure monitoring, cardiac output and flow monitoring, angioplasty, artificial vaso-occlusion, and cardiac support. Balloon catheters generally include a lumen that extends from the proximal end and provides fluid to the balloon for inflation. Examples of balloon catheters are disclosed in U.S. Pat. No. 4,813,934 to Engleson et al and U.S. Pat. No. 5,437,632 to Engelson et al. A balloon catheter with an adjustable shaft is shown in U.S. Pat. No. 5,968,012, to Ren et al.
For certain vascular malformations and aneurysms, it may be desirable to create an endovascular occlusion at the treatment site. A catheter is typically used to place a vaso-occlusive device or agent within the vasculature of the body either to block the flow of blood through a vessel by forming an embolus or to form such an embolus within an aneurysm stemming from the vessel. Formation of an embolus may also involve the injection of a fluid embolic agent such as microfibrillar collagen, Silastic beads, or polymeric resins such as cyanoacrylate. Ideally, the embolizing agent adapts itself to the irregular shape of the internal walls of the malformation or aneurysm. Inadvertent embolism due to an inability to contain the fluid agent within the aneurysm is one risk which may occur when using fluid embolic agents.
Mechanical vaso-occlusive devices may also be used for embolus formation. A commonly used vaso-occlusive device is a wire coil or braid which may be introduced through a delivery catheter in a stretched linear form and which assumes an irregular shape upon discharge of the device from the end of the catheter to fill an open space such as an aneurysm. U.S. Pat. No. 4,994,069, to Ritchart et al, discloses a flexible, preferably coiled, wire for use in a small vessel vaso-occlusion.
Some embolic coils are subject to the same placement risks as that of fluid embolic agents in that it is difficult to contain the occlusive coil within the open space of the aneurysm. A need exists for a delivery system which accurately places the occluding coil or fluid and ensures that the occluding coil or fluid does not migrate from the open space within the aneurysm. The delivery catheter must have a small diameter, have a highly flexible construction which permits movement along a small-diameter, tortuous vessel path, have a flexible method of placement to ensure accuracy, and must have a method to prevent coil or embolizing agent leakage.
This invention is a catheter or catheter section. Although it desirably has a balloon region located from distal of an inflatable member to proximal of that inflatable member, where the inflatable member is within the balloon region, it need not have a balloon region or an inflatable member. The inventive catheter has a flexible joint region located generally in the distal area of the catheter, often within that balloon region. The catheter includes a wire configured to flex the flexible joint region. Where the catheter includes an inflatable member, the flexible joint may variously be distal of the inflatable member, within the inflatable member, or proximal of the inflatable member. The flexible joint region preferably has a flexibility of up to about 90xc2x0. The flexible joint region, because the catheter wire may be too rigid, may also be manipulatable in a circular direction relative to the axis of the catheter.
The wire may be slidingly held, e.g., within a separate tubing. This tubing may potentially be used to aid in adjusting the flexibility of the joint region. This may be accomplished by several different variations. One variation utilizes a wire tubing having collinear consecutive sections of decreasing wall thickness. Alternatively, the wire tubing may be tapered according to the desired degree of joint flexibility. The tubing itself may be a braided tubing which may be of varying flexibility.
The flexible joint itself may be, for instance, a coil member, perhaps having a section with a pitch which is larger than adjacent coil pitches. The flexible joint may instead be a braid, perhaps with a section with a pic which is larger than the pic of one or more adjacent sections. The flexible joint may also be made up of a polymer tubing with a section which is softer than adjacent tubing polymers or a region having a wall thickness that is thinner than adjacent wall thickness.
In taking advantage of the flexibility and capabilities of the present invention, a variation capable of twisting in a helical or corkscrew-like manner may be accomplished with or without an inflatable member or balloon region. This variation is particularly useful in traversing tortuous vasculature and in making difficult approaches to aneurysms. This alternative varation utilizes a wire which may be wound about the guidewire or inner tubing and fixedly attached. It is thus possible to wind the wire any number of times or just a few degrees off the wire axis depending upon the vasculature being traversed and the degree of flexibility or twisting desired. Moreover, different variations may be developed capable of twisting in a left or right handed orientation.
The present invention may also incorporate various rapid exchange variations.
The inflatable member or balloon may be of a material selected from the group consisting of elastomers such as silicone rubber, latex rubber, natural rubber, butadiene-based co-polymer, EPDM, and polyvinyl chloride or thermoplastic polymers such as polyethylene, polypropylene, and nylon.